import java.sql.*;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
       // m1();
        //m2();
       // m3();
//m4();
        m5();
    }
    private static void m1(){
        Connection connection =null;
        PreparedStatement preparedStatement =null;
        ResultSet resultSet =null;
//1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url="jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection  = DriverManager.getConnection(url, "root", "root");
            /*if(connection!=null){
                System.out.println("连接成功");
            }*/
            //3.写sql
            String sql="select*from user";
            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);
            //5.执行sql
            resultSet = preparedStatement.executeQuery();
            //6.遍历结果
            while(resultSet.next()) {
               // resultSet.getInt(1);
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String pass = resultSet.getString(3);
                System.out.println(id + "----" + name + "----" + pass);
            }





        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally{
            //7.关闭资源
            try {
                if (resultSet!=null) {
                    resultSet.close();
                }
                if (preparedStatement!=null) {
                    preparedStatement.close();
                }
                if (connection!=null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }

        }
    }
    private static void m2(){
        //键盘录
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入要查询的用户名：");
        String name = scanner.nextLine();
        Connection connection =null;
        PreparedStatement preparedStatement =null;
        ResultSet resultSet =null;
//1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url="jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection  = DriverManager.getConnection(url, "root", "root");
            /*if(connection!=null){
                System.out.println("连接成功");
            }*/
            //3.写sql
            String sql="select*from user where name like ?";
            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);
            preparedStatement.setString(1,"%"+ name +"%");
            //5.执行sql
            resultSet = preparedStatement.executeQuery();
            //6.遍历结果
            while(resultSet.next()) {
                // resultSet.getInt(1);
                int id = resultSet.getInt(1);
                String username = resultSet.getString(2);
                String pass = resultSet.getString(3);
                System.out.println(id + "----" + username + "----" + pass);
            }





        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally{
            //7.关闭资源
            try {
                if (resultSet!=null) {
                    resultSet.close();
                }
                if (preparedStatement!=null) {
                    preparedStatement.close();
                }
                if (connection!=null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }

        }
    }
    //新增

    private static void m3(){
        Connection connection =null;
        PreparedStatement preparedStatement =null;

//1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url="jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection  = DriverManager.getConnection(url, "root", "root");
            /*if(connection!=null){
                System.out.println("连接成功");
            }*/
            //3.写sql
            String sql="insert into user(name,pass) values(?,?)";
            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);
            //设置参数
            preparedStatement.setString(1,"小明");
            preparedStatement.setString(2,"123456");
            //5.执行增加sql
            int result = preparedStatement.executeUpdate();
            if(result>0){
                System.out.println("增加成功");
            }else{
                System.out.println("增加失败");
            }


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally{
            //7.关闭资源
            try {

                if (preparedStatement!=null) {
                    preparedStatement.close();
                }
                if (connection!=null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }

        }
    }
    private static void m4(){
        Connection connection =null;
        PreparedStatement preparedStatement =null;

//1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url="jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection  = DriverManager.getConnection(url, "root", "root");
            /*if(connection!=null){
                System.out.println("连接成功");
            }*/
            //3.写sql
            String sql="update user set name=?,pass=? where id=?";
            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);
            //设置参数
            preparedStatement.setString(1,"王小明");
            preparedStatement.setString(2,"888");
            preparedStatement.setInt(3,19);
            //5.执行增加sql
            int result = preparedStatement.executeUpdate();
            if(result>0){
                System.out.println("修改成功");
            }else{
                System.out.println("修改失败");
            }


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally{
            //7.关闭资源
            try {

                if (preparedStatement!=null) {
                    preparedStatement.close();
                }
                if (connection!=null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }

        }
    }
    private static void m5(){
        Connection connection =null;
        PreparedStatement preparedStatement =null;

//1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url="jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection  = DriverManager.getConnection(url, "root", "root");
            /*if(connection!=null){
                System.out.println("连接成功");
            }*/
            //3.写sql
            String sql="delete from user where id=?";
            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);
            //设置参数

            preparedStatement.setObject(1,19);
            //5.执行增加sql
            int result = preparedStatement.executeUpdate();
            if(result>0){
                System.out.println("删除成功");
            }else{
                System.out.println("删除失败");
            }


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally{
            //7.关闭资源
            try {

                if (preparedStatement!=null) {
                    preparedStatement.close();
                }
                if (connection!=null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }

        }
    }
    }
